If atmospheric temperature and dew point are nearly equal, then the relative humidity is
Zero
50%
Almost 100%
unpredictable
Correct Answer :
C. Almost 100%
Related Questions
Pick out the wrong statement pertaining to the decomposition of PCl5 represented by, PCl5 PCl3 + Cl2.Degree of dissociation of PCl5 will
Decrease on addition of Cl2
Increase on addition of an inert gas at constant pressure
Decrease on increasing the pressure of the system
None of these
PVy = constant, holds good for an isentropic process, which is
Reversible and isothermal
Isothermal and irreversible
Reversible and adiabatic
Adiabatic and irreversible
Which of the following is affected by the temperature?
Fugacity
Activity co-efficient
Free energy
All (A), (B) & (C)
Entropy of an ideal gas depends upon its
Pressure
Temperature
Both (A) & (B)
Neither (A) nor (B)
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?
0
1
2
3
The equation, Cp - Cv = R, is true for __________ gas.
No
Any real
Only ideal
Both (B) and (C)
(∂H/∂T)P is the mathematical expression for
CV
Entropy change
Gibbs free energy
None of these
The work done in an adiabatic change in a particular gas depends upon changes in the __________ only.
Temperature
Specific heat
Volume
Pressure
The enthalpy change when ammonia gas is dissolved in water is called the heat of
Solution
Formation
Dilution
Combustion
Heat evolved/absorbed during conversion of a substance from one allotropic form to another is termed as the heat of
Fusion
Vaporisation
Transition
None of these
For a single component two phase mixture, the number of independent variable properties are
Two
One
Zero
Three
Pick out the correct statement:
In an isothermal system, irreversible work is more than reversible work
Under reversible conditions, the adiabatic work is less than isothermal work
Heat, work, enthalpy and entropy are all 'state functions'
Matter and energy cannot be exchanged with the surroundings in a closed system
Clapeyron Equation deals with the
Rate of change of vapour pressure with temperature
Effect of an inert gas on vapour pressure
Calculation of ΔF for spontaneous phase change
Temperature dependence of heat of phase transition
Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be
0
1
2
3
A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system is
3
4
5
6
A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, Δ S1 and Δ SR are the entropy changes of the system for the irreversible and reversible processes respectively)
Δ S1 is always < Δ SR
Δ S1 is sometimes > Δ SR
Δ S1 is always > Δ SR
Δ S1 is always = Δ SR
The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for
Expansion of a real gas
Reversible isothermal volume change
Heating of an ideal gas
Cooling of a real gas
If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
100
50
205
200
Co-efficient of Performance (COP) of a refrigerator is the ratio of the
Work required to refrigeration obtained
Refrigeration obtained to the work required
Lower to higher temperature
Higher to lower temperature
On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line (∂P/ ∂V)T are related as (where, y = Cp/Cv)
(∂P/∂V)S = (∂P/∂V)T
(∂P/∂V)S = [(∂P/∂V)T]Y
(∂P/∂V)S = y(∂P/∂V)T
(∂P/∂V)S = 1/y(∂P/∂V)T
A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is
349
651
667
1000
Chemical potential of ith component of a system is given by
μi = (∂F/∂ni)T, P, ni
μi = (∂A/∂ni)T, P, ni
μi = (∂F/∂ni)T, P
μi = (∂A/∂ni)T, P
To obtain integrated form of Clausius-Clapeyron equation, ln (P2/P1) = (ΔHV/R) (1/T1 - 1/T2) from the exact Clapeyron equation, it is assumed that the
Volume of the liquid phase is negligible compared to that of vapour phase
Vapour phase behaves as an ideal gas
Heat of vaporisation is independent of temperature
All (A), (B) & (C)
For any system, what is the minimum number of degrees of freedom?
0
1
2
3
Joule-Thomson co-efficient depends on the
Pressure
Temperature
Both (A) & (B)
Neither (A) nor (B)
In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in
Enhanced COP
Decreased COP
No change in the value of COP
Increased or decreased COP; depending upon the type of refrigerant
Chemical potential is a/an
Extensive property
Intensive property
Force which drives the chemical system to equilibrium
Both (B) and (C)
Pick out the wrong statement.
Minimum number of degree of freedom of a system is zero
Degree of freedom of a system containing a gaseous mixture of helium, carbon dioxide and hydrogen is 4
For a two phase system in equilibrium made up of four non-reacting chemical species, the number of degrees of freedom is 4
Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation
A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be __________ litres.
448
224
22.4
Data insufficient; can't be computed
Efficiency of a Carnot engine working between temperatures T1 and T2 (T1 < T) is
(T2 - T1)/T2
(T2 - T1)/T1
(T1 - T2)/T2
(T1 - T2)/T1